Security Settings About the Security System If Model 3 does not detect a authenticated phone or the key card and a locked door or trunk is opened, an alarm sounds and headlights and turn signals flash. To deactivate the alarm, press any button on the mobile app. To manually enable or disable the alarm system, touch Controls > Safety & Security > Security Alarm. When set to ON, Model 3 activates its alarm one minute after you exit, lock the doors, and an authenticated phone or key card is no longer detected. 98 Model 3 Owner's Manual